syzbot


general protection fault in __tun_detach

Status: closed as invalid on 2025/09/05 13:36
Subsystems: net
[Documentation on labels]
First crash: 66d, last: 66d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc001fffe000: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x00000000ffff0000-0x00000000ffff0007]
CPU: 0 UID: 0 PID: 16953 Comm: syz-executor Not tainted 6.16.0-syzkaller-06574-gd9104cec3e8f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:tun_flow_delete_by_queue drivers/net/tun.c:371 [inline]
RIP: 0010:__tun_detach+0x961/0x1560 drivers/net/tun.c:606
Code: 02 00 00 e8 21 21 49 fb 48 bd 00 00 00 00 00 fc ff df 4d 85 ed 0f 84 6a 02 00 00 e8 09 21 49 fb 4c 89 eb 49 89 dc 49 c1 ec 03 <41> 80 3c 2c 00 74 08 48 89 df e8 e0 43 ac fb 4c 8b 2b 4c 8d 73 30
RSP: 0018:ffffc9001ce578b8 EFLAGS: 00010206
RAX: 1ffff110064fd605 RBX: 00000000ffff0000 RCX: ffff8880268b0000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9001ce57840
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520039caf08 R12: 000000001fffe000
R13: 1ffff11009393923 R14: ffff8880327e8d80 R15: ffff8880327e9590
FS:  0000000000000000(0000) GS:ffff888125c80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9119b8cf98 CR3: 000000007aeca000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 tun_detach drivers/net/tun.c:637 [inline]
 tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3433
 __fput+0x449/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x22e0 kernel/exit.c:964
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a5a38d57c
Code: Unable to access opcode bytes at 0x7f4a5a38d552.
RSP: 002b:00007ffc28301d70 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 00007f4a5a38d57c
RDX: 0000000000000030 RSI: 00007ffc28301e30 RDI: 00000000000000f9
RBP: 00007ffc28301ddc R08: 0000000000000000 R09: 00007ffc28301ae7
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000258
R13: 00000000000927c0 R14: 00000000000a3c59 R15: 00007ffc28301e30
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:tun_flow_delete_by_queue drivers/net/tun.c:371 [inline]
RIP: 0010:__tun_detach+0x961/0x1560 drivers/net/tun.c:606
Code: 02 00 00 e8 21 21 49 fb 48 bd 00 00 00 00 00 fc ff df 4d 85 ed 0f 84 6a 02 00 00 e8 09 21 49 fb 4c 89 eb 49 89 dc 49 c1 ec 03 <41> 80 3c 2c 00 74 08 48 89 df e8 e0 43 ac fb 4c 8b 2b 4c 8d 73 30
RSP: 0018:ffffc9001ce578b8 EFLAGS: 00010206
RAX: 1ffff110064fd605 RBX: 00000000ffff0000 RCX: ffff8880268b0000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9001ce57840
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520039caf08 R12: 000000001fffe000
R13: 1ffff11009393923 R14: ffff8880327e8d80 R15: ffff8880327e9590
FS:  0000000000000000(0000) GS:ffff888125c80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9119b8cf98 CR3: 000000007aeca000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	02 00                	add    (%rax),%al
   2:	00 e8                	add    %ch,%al
   4:	21 21                	and    %esp,(%rcx)
   6:	49 fb                	rex.WB sti
   8:	48 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%rbp
   f:	fc ff df
  12:	4d 85 ed             	test   %r13,%r13
  15:	0f 84 6a 02 00 00    	je     0x285
  1b:	e8 09 21 49 fb       	call   0xfb492129
  20:	4c 89 eb             	mov    %r13,%rbx
  23:	49 89 dc             	mov    %rbx,%r12
  26:	49 c1 ec 03          	shr    $0x3,%r12
* 2a:	41 80 3c 2c 00       	cmpb   $0x0,(%r12,%rbp,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 e0 43 ac fb       	call   0xfbac4419
  39:	4c 8b 2b             	mov    (%rbx),%r13
  3c:	4c 8d 73 30          	lea    0x30(%rbx),%r14

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/05 15:40 net-next d9104cec3e8f 904e669c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce general protection fault in __tun_detach
* Struck through repros no longer work on HEAD.